Hydraulic control valve



May 9, 1939. A, KEEL 2,157,707

lHYDRAULIC: CONTROL VALVE Filed Jan. 10, 1936 Patented May 9, 193.9

PATENT oFElcE HYDRAULIC CONTROL vALvE Adolf Keel, Highland Park, Mich., assignor to Ex-Cell-O Corporation, a corporation of Michigan Application January 1o, 1936, 'serial No. 58,501

claims.

The present invention relates to improvements in control valves for hydraulic systems in machine element drives, and has particular reference to a new andimproved orifice feed valve 5 adapted to control the rate of movement by restricting the discharge ow of the fluid pressure medium.

'Ihe'orifice feed valve will build up a pressure in .the discharge side of the system. The rate of movement is determined by the flowl through the valve, and' hence by the pressure drop across the orifice means. Where the built-up pressure is constant, the pressure drop is constant. However, in practice, the built-up pressure is subject to variation due to otherfactors affecting the drive, and these variations tend to alter the rate of movement. One of the primary features of the present invention therefore resides in the provision of an orifice control valve having novel means for automatically maintaining a constant pressure drop across the orifice means regardless of pressure variations at the inlet.

A further object is to provide a new and improved feed control valve having a plurality of .:5 selective orifices in the discharge line of a hydraulic motor, and a, governor for maintaining constant the ow characteristics of the orifices under all pressure conditions,

Still another object resides in the provision of. a novel feed control valve which is adapted lto be interposed in the discharge side of a hydraulic system, and which has a manually adjustable flow control orifice in front of and in series with an automatic valve for determining the pressure at the discharge side of the control orifice, and in which the automatic valve is operable by the differential of the inlet and discharge pressures of the control orifice in opposition` to spring pressure to maintain said differio ential constant.

Further objects and advantages will become apparent as the description proceeds.A

In the accompanying drawing, Figure 1 is a fragmentary sectional view of a hydraulic system with a valve embodying the features of my invention. .7. i v

Fig. 2 is a transverse sectional view of the valve taken along line 2-2 of Fig..1.

Fig. 3` is a fragmentary sectional view taken Referring more particularly to the drawing, the feed control valve, constituting the preferred embodiment of the invention, is adapted to be disposed in the path, and to control the flow, of

, fluid discharged from a hydraulic motore In the present instance, I have shown a motor of the reciprocatory type comprising a cylinder l0 and a piston I I slidable therein. The motor is adapted particularly for driving a reciprocatory element, such as a work or tool carriage (not shown), of a machine tool, the cylinder i0 being rigidly attached to the machine base (not shown) and the piston i I having a rod I2 attached to the carriage.

The fluid control mechanism for the motor I0,

I I may be of any suitable type, and for purposes 10 of illustration is herein shown and described as comprising a supply line I3 which is adapted to receive a fluid working medium, such as oil, from a pressure source (not shown), and which is adapted to be connected selectively by a reversing valve Ill to one or the other of two lines I5 and I6 connected respectively to opposite ends of the cylinder I0. f

The reversing valve It per se forms no part of the presentinvention, and hence the-details thereof are not described. The valve It has a discharge line I l', and may be actuated reversibly by any suitable means (not shown) so that it will in one position connect the line I3 to the line I5. and the line I6 to the line I 'i to effect movement of the piston I t to the right, and in anothern position connect the lines I3 and I6 and the'lines I5 and I'l (see Fig. 1) to effect movement of the piston to the left. In either position of the valve It, the line Il is connected to the discharge end 30 of the cylinder ill.

The feed control valve, indicated generally at. I8, is interposed in the line il, and comprises orifice means for restricting the flow of dis'- charge fluid from the cylinder I0 to control the 35 rate of movement of the piston II and hence the machine tool carriage. In its preferred form, Ythe valve I8 has two adjustable selective restricted orifice valves I9 and 20 housed in a body 2i. AThe yalves Iii and 20 respectively comprise 40 hollow cylindrical plugs 22 and 23 rotatably disposed in two parallel bores 2t and 25. Two inlet passages 26 and 21 open respectively tangentially to the adjacent sides of the bores or valve chambers 24 and 25,- and define longitudinally tapered 45 ports 28 and 29. Opening respectively from the peripheries of the bases 2lland ,25 are two ports to connect the ports 28 and 30, the helical marginal edge portion of the peripheral surface partially closing the port 38 in various degrees to obtain the desired orifice restriction, or may be rotated to close the port 30 when the valve I9 is not to be used.. When diierent rates of carriage movement or feed are desired, the plugs 22 and 23 are adjusted to obtain orifice openings of dilerent size through the ports 30 and 3|.

To provide means for adjusting the orice valves I9 and 20 independently, each of the plugs 22 is rotatably enclosed within the body 2| by a screw plug 35, and is provided with an axial shaft 36 journaled in and extending through a support, such as a wall 31 forming part of the machine base, to which the body 2l is suitably secured or bolted. A dial 38 is splined to the shaft 36, and is held against the wall 31 by a nut 39. The outer end of the shaft 36 is squared for engagement by a suitable manual tool (not shown). The nut 39 is loose during adjustment, and then is tightened to lock the dial 38 and the plug in place, and to obtain a tight seal between theplug and the inner end of the valve bore.

The passages 26 and 21, leading to the orice valves I9 and 20, open in spaced relation from two annular grooves 4D and 4I in a bore 42 formed in the body 2|, and constituting the chamber of an orifice selector valve 43. 'Ihe opposite ends of the bore 42 are closed by apertured blocks 44. An annular groove 45 in the bore 42, intermediate the grooves 40 and 4| is connected to the line I1. Slidably disposed in the bore 42 is a valve plunger 46 formed with a peripheral groove 4l which in one end position will connect the grooves 40 and 45 and close the groove 4| to select the orifice valve I9 (see Fig. l), and in the other end position will connect the grooves 4I and 45 and close the groove 40 to select the oriiice valve 20.

To provide means for adjusting the selector valve 43, the opposite ends of the bore 42 are connected 'respectively through lines 48 and 49 to a suitable control valve 50 having a pressure inlet line I connected to the line I3, and having a drain line 52,. The details of the valve 50 per se form no part of the present invention, and hence are not described. The valve 50 may be operated by any suitable means, and is adapted in one position to connect the lines 5I and 52 respectively to the lines 48 and 49, and in another position to reverse the connections.

In the operation of the motor I0, II, the discharge of fluid is controlled by the flow law of oriiices. The restriction to iiow causes pressure to build up in the discharge end of the cylinder I0, and resist the movement of the pistons II by thc fluid in the pressure end. The rate of travel is therefore controlled and determined by the size of the particular orifice connected in the discharge line by the selector valve 43. Since there are two adjustable orifice valves, two different rates of feed or traverse are available, and each is subject to individual adjustment.

The pressure is also inuenced by the working resistance set up in the machine operation by the engagement between the tool and the work. If this working resistance varies, the pressure drop across the orifice tends to vary with the result that a constant speed will not be obtained. Thus, when the tool leaves the work, the working resistance ceases, and the speed of the piston tends to increase. This tends to increase the pressure in the discharge end of the cylinder II'I and hence the pressure drop across the orlce. thereby tending to cause an increase in the rate of fluid discharge.

The maintenance of a constant speed of travel is very desirable, and hence one of the primary features of the present invention resides in the provision of means for maintaining a constant `pressure drop across the orifice valve I9 or 20.

In the present instance, this means comprises a governor valve 53 which is automatically operable in response to the differential between the pressures at opposite sides of the orifice valves to control the pressure in the orice discharge passage 32.

'I'he governor valve' 53 comprises a. hollow plunger 54 reciprocably disposed in a bore 55 formed in the body 2|, and closed at opposite ends by plugs 56 and 51. One end of the plunger 54 is closed and adapted to seat against the plug 56. A coiled compression spring 58 is seated at one end in a recess 59 in the plug 5'I, and at the other end against the inner face of the closed end of the plunger 54, and tends to urge the latter to the left. The passage 32 from the orice valves I9 and 20 opens to an annular groove 6U in the right end of the bore 55. Formed in the bore 55 adjacent the right end is a second annular groove 6I which opens to the drain. A plurality of peripherally spaced generally longitudinally V-shaped notches 62 are formed in the periphery of the right end of the plunger 54, and are movable into various degrees of communication with the groove 6I to provide a restricted orice valve connection between the passage 32 and the drain of progressively increasing size as the plunger is moved to the left under the influence of the spring 58. 'I'he left end of the bore 55 is connected through a line 63 to the line I1 at the inlet side of the valve 43.

In operation, when the motor I0, |I is idle, no pressure will exist in the lines I'I and 63, and hence the passage through the notches 62' will be wide open. When movement is instituted,

pressurel will be created in the line I'I, and will tend to urge the plunger 54 to the right against the action of the spring 58. For a given constant discharge pressure, the plunger 54 will seek a position of equilibrium dening a predetermined pressure drop across the connected orice. If the discharge pressure should drop, the plunger 54 will move to the left, thereby increasing the opening through the notches 62 to decrease the pressure in the passage 32. Conversely, if the discharge pressure should increase, the pressure in the passage 32 will be increased. As a result, the pressure drop across the connected orifice will be maintained substantially constant to maintain a constant rate of discharge regardless of pressure fluctuations in the discharge end of the cylinder, and thereby to maintain a substantially constant rate of piston travel under varying conditions.

I claim as my invention:

1. In combination with a line adapted to receive fluid expelled from a reciprocatory hydraulic motor for translating a machine element. two adjustable orifice valves, means for selectively connecting one or the other of said valves to said line to restrict the discharge of the fluid in accordance with the flow law of orifices, and means responsive to the pressure in said line at the inlet side of said orifice valves for automatically regulating the pressure at the discharge side of said valves to maintain a subf alamo? stantially constant pressure drop across said valves. I

2. An orifice feed valve comprising, in combination, a body having a selector valve chamber. two oriice valve chambers and a governor valve chamber, an inlet passage opening to said iirst mentioned chamber, two outlet passages connecting said iirst mentioned chamber to said orice valve chambers, a third passage opening in parallel from said orice valve chambers to said governor .valve chamber, and a drain passage opening from said last mentioned chamber, a selector valve member adjustably mounted in said rst mentioned chamber for connecting said inlet passage selectively to one or the other of said outlet passages, two independently adjustable orifice valve members mounted in said orice valve chambers, a governor valve member `adjustably -mounted in said governor valve chamber, spring means tending to bias said governor valve member in one direction to increase the discharge opening to said drain passage, and a cross passage connecting said inlet passage to said governor valve chamber to supply pressureuid tending to adjust said governor valve vtomatically operable to maintain a substantially constant pressure dierential across said valves for any given adjustment of said rst mentioned means regardless of pressure fluctuations.

4. In combination with a'4 line adapted to receive uid expelled from a hydraulic motor for translating a machine element, a plurality of parallel orifice valves each of which is adapted to be operatively connected in said line to establish an independent path of ow and when so connected is adapted to restrict the :dow of fluid through said line in accordance with the ilow law of orifices, means for selectively connecting said valves in said line, and valves means in said line in series with said orice valves and automatically adjustable in response to pressure uctuations in said line to maintain a substantially constant pressure of orifices, adjustable means for connecting said valves selectively in Asaid line, andmeans automatically operable to maintain a substantially constant pressure differential acrosssaid valves for any given adjustment of said ilrst mentioned means regardless of pressure uctuations.

ADOLF KEEL.

` differential Aacross said orice valves for any given selective 

